For example, in a wireless communication network employing an Internet protocol (IP) group (hereinafter occasionally referred to as “wireless IP network”), so-called mobile IP is defined in order to improve the mobility of wireless communication apparatus (e.g. non-patent literature 1).
Mobile IP uses a care-of IP address (Care of Address) that is dynamically allocated according to the location of wireless communication apparatus. Non-patent literature 1: C. Perkins, “IP Mobility Support (RFC2002)”, [online], October 1996, IETF, [searched on Mar. 15, 2006], downloaded from the web site of the Internet Engineering Task Force.